Biology Cell Cycle and Osmosis

Questions and Answers

What is the primary role of the cell membrane in relation to homeostasis?

To provide structural support to the cell

To facilitate energy production

To assist in viral replication

To regulate transport in and out of the cell (correct)

What mechanism is NOT typically involved in transport across the cell membrane?

Facilitated diffusion

Protein synthesis (correct)

Simple diffusion

Active transport

How does the phospholipid bilayer of the cell membrane contribute to selective permeability?

It allows all substances to pass freely due to its fluid nature.

Only hydrophilic substances can interact with the tails for passage.

The hydrophobic tails prevent water from entering the cell.

The arrangement of phospholipids blocks large molecules, enabling selective transport. (correct)

Why do viruses need to hijack a host cell for replication?

They lack the cellular machinery to reproduce on their own. Signup and view all the answers

Which statement best describes the fluid mosaic model of the cell membrane?

Various proteins float in or on the fluid lipid bilayer. Signup and view all the answers

What happens to cells when a person drinks a lot of salt water?

Cells lose water and dehydrate. Signup and view all the answers

What term is used for a cell that has the potential to differentiate into any cell type?

Totipotent Signup and view all the answers

Which of the following best describes the function of cyclins in the cell cycle?

They promote mitosis after a specific concentration is reached. Signup and view all the answers

What is a common physiological result of dehydration caused by salt water intake?

Loss of cell turgor pressure. Signup and view all the answers

How do stem cells differentiate into specialized cells?

By exposure to external growth factors. Signup and view all the answers

What occurs in cancer regarding the cell cycle?

G1 phase is bypassed and mitosis is unregulated. Signup and view all the answers

What is the primary role of growth factors in the cell cycle?

They encourage growth and cell division. Signup and view all the answers

In a multicellular organism, what is a consequence of uncontrolled cell division?

Development of tumors and cancer. Signup and view all the answers

What is the primary function of transport proteins in the cell membrane?

To selectively allow certain substances to pass through Signup and view all the answers

In which type of transport does a substance move against its concentration gradient?

Active transport Signup and view all the answers

What effect does a hypertonic solution have on plant cells?

It causes cells to become plasmolyzed Signup and view all the answers

How does facilitated diffusion differ from simple diffusion?

It occurs through specialized transport proteins Signup and view all the answers

Which solution condition is ideal for animal cells to maintain homeostasis?

Isotonic solution Signup and view all the answers

Which mechanism requires ATP to function?

Active transport Signup and view all the answers

What occurs to a plant cell in a hypotonic solution?

It becomes turgid and firm Signup and view all the answers

What defines the fluid mosaic model of the cell membrane?

Dynamic arrangement of various molecules Signup and view all the answers

Study Notes

Cell Biology and Transport Mechanisms

Water moves from regions of higher water concentration to lower when the solute concentration is higher outside cells, causing dehydration in cells exposed to saltwater.
Cells in multicellular organisms undergo a regulated cell cycle for growth, repair, and development, starting from a single fertilized cell.
Stem cells are undifferentiated, influenced by neighboring cells to specialize; differentiated cells perform specific functions.
Prokaryotes lack specialization and fulfill all cellular roles within a single cell.
Types of stem cells include:
- Totipotent: can transform into any cell type.
- Pluripotent: can become most cell types.
- Multipotent: limited to a few specific cell types.

Cell Cycle Regulation

The cell cycle is controlled by growth factors (external signals) and cyclins (internal proteins necessary for progression).
Cancer disrupts normal cell cycle regulation, often leading to unregulated cell division with no G1 phase.
Selectively permeable cell membranes allow only certain substances through, with the help of transport proteins.

Transport Mechanisms

Simple diffusion allows particles to move across membranes from high to low concentration without energy.
Facilitated diffusion utilizes transport proteins for particle movement across membranes, also without energy.
Active transport requires ATP to move substances against their concentration gradient via channels or pumps.

Osmosis and Cellular Response to Solutions

Cells respond differently to hypertonic, hypotonic, and isotonic conditions.
- Isotonic: favorable for animal cells, maintaining normal water balance.
- Hypotonic: preferred by plant cells, enhancing turgidity and structural support.
Water moves by osmosis from high water concentration to low, impacting cell shape and rigidity.

Cell Membrane Structure and Function

The fluid mosaic model describes the dynamic nature of the phospholipid bilayer, which comprises diverse and movable components.
Phospholipid bilayer's hydrophobic tails create selective permeability, limiting how substances pass through, necessitating specific channel proteins for some materials to enter cells.

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Description

This quiz explores the concepts of osmosis and the cell cycle in biology. Understand how solute concentrations affect water movement in cells and the implications of drinking salt water on cell hydration. Delve into the processes of cell division and its importance in multicellular organisms.